Heidi Strbak arrives at the Supreme Court in Brisbane, Thursday, November 16, 2017. Ms Strbak is attending a contested sentence hearing for the manslaughter of her four-year-old son Tyrell Cobb on May 24, 2009. AAP Image - Glenn Hunt

Innocent Lives: Calls for tougher child killer laws

CALLS for a drastic overhaul of laws to deal with child killers and greater scrutiny of backroom deals have intensified after Heidi Strbak was sentenced to nine years in jail for beating her son Tyrell Cobb to death.

Of the 33 people charged with the manslaughter of a child in the past 12 years, not one has received more than a 10-year jail term.

Strbak was found to have inflicted two fatal blows that caused internal bleeding and the contents of Tyrell's stomach to leak, before the four-year-old's painful death on May 24, 2009.

The 34-year-old will serve four years in jail until she can apply for parole.

Strbak had pleaded guilty to manslaughter on the grounds of criminal negligence, and continued to deny hitting Tyrell when Justice Peter Applegarth sentenced her yesterday.

"I have not caused the injuries that I am being blamed for and I believe that it is a mistake and an injustice not only towards Tyrell, but to my family, his other family and myself," she said.

The sentence was in line with precedent cases, but in the face of a child protection crisis that has sparked multiple reviews, advocates such as Bravehearts founder Hetty Johnston have called on the State Government to give judges the power to impose tougher penalties.

Tyrell Cobb died in 2009.

"We've been saying that for a decade. Anybody that kills a child either by virtue of their own hand or as a bystander should get life," she said.

"Manslaughter or murder is irrelevant. It's child killer."

Strbak's sentence comes after a spate of similar cases this year, including that of Rick Cataldo, who was given eight years in jail for killing his seven-week-old daughter, to be eligible for parole after serving almost four years.

It led criminologist Terry Goldsworthy to call for mandatory sentencing.

"At what point does the justice system catch up with reality," he said. "It seems like we are more concerned about one-punch killers and domestic violence than we are about these child killers."

Hemi Goodwin-Burke was bashed to death by Matthew James Ireland.

Strbak's ex-partner Matthew Scown sparked public outrage when he walked from court grinning after being given a four-year manslaughter sentence for failing to provide the medical care that Tyrell desperately needed as he lay dying in his mother's Gold Coast unit.

His sentence - of which he served three years - was discounted because of his co-operation with authorities, although details of the deal are bound by strict legislation.

Ms Johnston said there should be no backroom deals, but criminal lawyer Bill Potts said consideration could be given to judges having discretion to make details public.

"The court and everybody is straightjacketed by the legislation," he said. "There's at least some room for discussion, I think, as to whether the good intentions of the legislation are in fact overborne by common sense."

According to the Queensland Sentencing Advisory Council (QSAC), which is reviewing sentences for child killers, 33 people were sentenced for the manslaughter of a child between 2005 and 2017, with sentences ranging from 18 months to 10 years.

During the same period, 24 offenders were sentenced for the murder of a child, which has a mandatory life sentence.

Strbak and Scown were originally charged with murder, but it was downgraded after prosecutors decided there was insufficient evidence for a murder conviction.

Prosecutor Phil McCarthy said Strbak chose not to take Tyrell to a doctor because she did not want to be accused of neglect and had concealed her son's deteriorating condition from family. The court heard although there was no evidence of sustained abuse, Scown said Strbak slapped Tyrell the weekend he died and neighbours reported she was angry at him.

Defence barrister Greg McGuire said Strbak had no criminal history before or since Tyrell died and she had become "public enemy No.1" due to publicity surrounding the case.

Justice Applegarth said child abuse and education for parents needed to be addressed.

"The sad thing is … I wouldn't hazard a guess how many little children in this state have been punched in the stomach," the judge said.

OTHER NOTABLE SENTENCES

Paige Humpheys who was a victim of Michael John Humpreys.

Michael Humphreys, nine-year sentence

-Tortured his daughter Paige to death in 2012 until she died at just 31 days' old with injuries including a fractured skull, ribs and legs and underlying brain injury.

-Pleaded guilty to torture and manslaughter and was sentenced to nine years' in jail, to be eligible for parole in 2021

Rick Cataldo, eight-year sentence

Michelle Leask, five-year sentence

-Rick Cataldo bashed his seven-week-old daughter Lily to death in 2012 and then refused to take her to hospital.

-Cataldo pleaded guilty to manslaughter and was given an eight-year sentence to be immediately eligible for parole taking into account time already served

- Leask also pleaded guilty to manslaughter, but on the ground of criminal negligence, and received a five-year suspended sentence

Kyhesha-Lee Joughin dies in 2013 following a punch to the stomach.

Matthew Williamson, nine-year sentence

Christopher Kent, two-year sentence

-Matthew Williamson punched his daughter Kyhesha-Lee Jougin in the stomach so hard he caused a fatal bowel injury and she died in 2013

-Williamson pleaded guilty to manslaughter but denied he caused the fatal injuries. A judge found otherwise and he was sentenced to nine years' in jail to serve at least seven years.

-His flatmate, Christopher Kent, received a two-year sentence for manslaughter after he turned a blind eye to the abuse. He gave evidence against Williamson.